The present invention relates to pneumatic tools for seating the beads of tubeless tires onto tubeless wheels and rims.
To inflate a tubeless tire to a desired operating air pressure, it is first necessary to seat, or seal, the beads of the tire onto the bead area of the wheel or rim. Seating the tire beads to the bead area of the wheel or rim creates a pressurizable chamber within the tire that may then be charged with air through a conventional valve stem mounted through the wheel or rim. The well-known problem faced by operators when mounting large tubeless tires, such as 24.5.times.8.25 truck tires for example, is that it is relatively difficult to seat both of the tire beads simultaneously due to the weight and stiffness of the side walls of the tires.
In recent years, mechanical means for seating the beads of large tubeless tires, such as circular bands around the tire tread that squeeze the tire about its circumference to expand the tire's side walls outwardly until the tire's beads are both in contact with the bead area of the wheel or rim, have given way to high pressure pneumatic tools. Pneumatic tools instantaneously inject a large volume of highly pressurized air into the gap between the wheel or rim and an unseated tire bead, while pressurized air is simultaneously being injected into the tire through the conventional valve stem. At the moment the pneumatic tool is activated, there is instantaneously a larger volume of air entering the tire than is escaping around the unseated tire beads, and the tire's side walls rapidly expand. The tire beads then come into seating contact with the bead area of the wheel or rim. The tire and wheel or rim then instantaneously become a pressurizable chamber that is further pressurized by the air entering the chamber through the conventional valve stem.
Numerous pneumatic tools for seating tubeless tire beads in the general manner described above are known in the prior art. Most are of a relatively complex design and/or have cumbersome adjustment mechanisms by which they must be adjusted for use with tubeless tires and wheels or rims of varying diameters. Most are also designed to inject air symmetrically about the wheel or rim, either through a continuous ring around the wheel or rim or through a discontinuous ring comprising two or more arc-shaped plenum symmetrically positioned about the wheel or rim. For example, U.S. Pat. No. 3,683,991 to Ruhland et al. discloses a pneumatic bead seating device that has a C-shaped configuration that places two arcuate housings in mirror image relationship around a wheel or rim. The fixed positioning of the C-shaped configuration of the embodiment of the Ruhland et al. invention illustrated in FIGS. 6-10 makes it difficult to use the illustrated device with smaller diameter wheels or rims. As illustrated in FIG. 10 of Ruhland et al., it is suggested that the Ruhland et al. device be physically raised by the operator above a smaller wheel or rim and held in place by the operator without any direct stabilizing contact with the wheel or rim while jets of highly compressed air are directed downwardly from the elevated device toward the gap between the smaller wheel or rim and tire bead below.